The objective of the proposed research are the following: 1. To characterize in detail the subunit structure of Lumbricus hemoglobins. This will include determination of the molecular weight and number of copies of the constituent polypeptide chains and of their arrangement in the subunits making up the native molecule. 2. To compare the subunit structure of Lumbricus hemoglobin with the subunit structure of other annelid hemoglobins, namely those of Arenicola, Tubifex and Limnodrilus. The subuniit structures of hemoglobins will be determined using gel filtration and polyacrylamide gel electrophoresis in the presence of detergents and at alkaline pH. The number of copies of the isolated subunits will be determined by quantitative polyacrylamide gel electrophoresis. End group analysis will be performed on the isolated subunits and the identification of the constituent polypeptide chains will be completed using stepwise Edman degradation whenever necessary. Cross-linking of the subunits in the intact molecule will be carried out using bifunctional reagents followed by identification of the cross-linked subunits using previously developed methods of dissociation. The resulting topology of the subunits will be compared with proposed model of the quaternary structure of Lumbricus hemoglobin.